/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/

/*
 *  X.509 Certificate Signing Request (CSR) parsing
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */
/*
 *  The ITU-T X.509 standard defines a certificate format for PKI.
 *
 *  http://www.ietf.org/rfc/rfc5280.txt (Certificates and CRLs)
 *  http://www.ietf.org/rfc/rfc3279.txt (Alg IDs for CRLs)
 *  http://www.ietf.org/rfc/rfc2986.txt (CSRs, aka PKCS#10)
 *
 *  http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf
 *  http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
 */

#include "tls/config.h"

#if defined(MBEDTLS_X509_CSR_PARSE_C)

#include "tls/x509_csr.h"
#include "tls/oid.h"

#include <string.h>

#if defined(MBEDTLS_PEM_PARSE_C)
#include "tls/pem.h"
#endif

#if defined(MBEDTLS_PLATFORM_C)
#include "tls/platform.h"
#else
#include <stdlib.h>
#include <stdio.h>
#define mbedtls_free       free
#define mbedtls_calloc    calloc
#define mbedtls_snprintf   snprintf
#endif

#if defined(MBEDTLS_FS_IO) || defined(EFIX64) || defined(EFI32)
#include <stdio.h>
#endif

/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize(void *v, size_t n)
{
	volatile unsigned char *p = v;
	while (n--) {
		*p++ = 0;
	}
}

/*
 *  Version  ::=  INTEGER  {  v1(0)  }
 */
static int x509_csr_get_version(unsigned char **p, const unsigned char *end, int *ver)
{
	int ret;

	if ((ret = mbedtls_asn1_get_int(p, end, ver)) != 0) {
		if (ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
			*ver = 0;
			return (0);
		}

		return (MBEDTLS_ERR_X509_INVALID_VERSION + ret);
	}

	return (0);
}

/*
 * Parse a CSR in DER format
 */
int mbedtls_x509_csr_parse_der(mbedtls_x509_csr *csr, const unsigned char *buf, size_t buflen)
{
	int ret;
	size_t len;
	unsigned char *p, *end;
	mbedtls_x509_buf sig_params;

	memset(&sig_params, 0, sizeof(mbedtls_x509_buf));

	/*
	 * Check for valid input
	 */
	if (csr == NULL || buf == NULL || buflen == 0) {
		return (MBEDTLS_ERR_X509_BAD_INPUT_DATA);
	}

	mbedtls_x509_csr_init(csr);

	/*
	 * first copy the raw DER data
	 */
	p = mbedtls_calloc(1, len = buflen);

	if (p == NULL) {
		return (MBEDTLS_ERR_X509_ALLOC_FAILED);
	}

	memcpy(p, buf, buflen);

	csr->raw.p = p;
	csr->raw.len = len;
	end = p + len;

	/*
	 *  CertificationRequest ::= SEQUENCE {
	 *       certificationRequestInfo CertificationRequestInfo,
	 *       signatureAlgorithm AlgorithmIdentifier,
	 *       signature          BIT STRING
	 *  }
	 */
	if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
		mbedtls_x509_csr_free(csr);
		return (MBEDTLS_ERR_X509_INVALID_FORMAT);
	}

	if (len != (size_t)(end - p)) {
		mbedtls_x509_csr_free(csr);
		return (MBEDTLS_ERR_X509_INVALID_FORMAT + MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
	}

	/*
	 *  CertificationRequestInfo ::= SEQUENCE {
	 */
	csr->cri.p = p;

	if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
		mbedtls_x509_csr_free(csr);
		return (MBEDTLS_ERR_X509_INVALID_FORMAT + ret);
	}

	end = p + len;
	csr->cri.len = end - csr->cri.p;

	/*
	 *  Version  ::=  INTEGER {  v1(0) }
	 */
	if ((ret = x509_csr_get_version(&p, end, &csr->version)) != 0) {
		mbedtls_x509_csr_free(csr);
		return (ret);
	}

	csr->version++;

	if (csr->version != 1) {
		mbedtls_x509_csr_free(csr);
		return (MBEDTLS_ERR_X509_UNKNOWN_VERSION);
	}

	/*
	 *  subject               Name
	 */
	csr->subject_raw.p = p;

	if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
		mbedtls_x509_csr_free(csr);
		return (MBEDTLS_ERR_X509_INVALID_FORMAT + ret);
	}

	if ((ret = mbedtls_x509_get_name(&p, p + len, &csr->subject)) != 0) {
		mbedtls_x509_csr_free(csr);
		return (ret);
	}

	csr->subject_raw.len = p - csr->subject_raw.p;

	/*
	 *  subjectPKInfo SubjectPublicKeyInfo
	 */
	if ((ret = mbedtls_pk_parse_subpubkey(&p, end, &csr->pk)) != 0) {
		mbedtls_x509_csr_free(csr);
		return (ret);
	}

	/*
	 *  attributes    [0] Attributes
	 *
	 *  The list of possible attributes is open-ended, though RFC 2985
	 *  (PKCS#9) defines a few in section 5.4. We currently don't support any,
	 *  so we just ignore them. This is a safe thing to do as the worst thing
	 *  that could happen is that we issue a certificate that does not match
	 *  the requester's expectations - this cannot cause a violation of our
	 *  signature policies.
	 */
	if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC)) != 0) {
		mbedtls_x509_csr_free(csr);
		return (MBEDTLS_ERR_X509_INVALID_FORMAT + ret);
	}

	p += len;

	end = csr->raw.p + csr->raw.len;

	/*
	 *  signatureAlgorithm   AlgorithmIdentifier,
	 *  signature            BIT STRING
	 */
	if ((ret = mbedtls_x509_get_alg(&p, end, &csr->sig_oid, &sig_params)) != 0) {
		mbedtls_x509_csr_free(csr);
		return (ret);
	}

	if ((ret = mbedtls_x509_get_sig_alg(&csr->sig_oid, &sig_params, &csr->sig_md, &csr->sig_pk, &csr->sig_opts)) != 0) {
		mbedtls_x509_csr_free(csr);
		return (MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG);
	}

	if ((ret = mbedtls_x509_get_sig(&p, end, &csr->sig)) != 0) {
		mbedtls_x509_csr_free(csr);
		return (ret);
	}

	if (p != end) {
		mbedtls_x509_csr_free(csr);
		return (MBEDTLS_ERR_X509_INVALID_FORMAT + MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
	}

	return (0);
}

/*
 * Parse a CSR, allowing for PEM or raw DER encoding
 */
int mbedtls_x509_csr_parse(mbedtls_x509_csr *csr, const unsigned char *buf, size_t buflen)
{
	int ret;
#if defined(MBEDTLS_PEM_PARSE_C)
	size_t use_len;
	mbedtls_pem_context pem;
#endif

	/*
	 * Check for valid input
	 */
	if (csr == NULL || buf == NULL || buflen == 0) {
		return (MBEDTLS_ERR_X509_BAD_INPUT_DATA);
	}
#if defined(MBEDTLS_PEM_PARSE_C)
	mbedtls_pem_init(&pem);

	/* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
	if (buf[buflen - 1] != '\0') {
		ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
	} else {
		ret = mbedtls_pem_read_buffer(&pem, "-----BEGIN CERTIFICATE REQUEST-----", "-----END CERTIFICATE REQUEST-----", buf, NULL, 0, &use_len);
	}

	if (ret == 0) {
		/*
		 * Was PEM encoded, parse the result
		 */
		if ((ret = mbedtls_x509_csr_parse_der(csr, pem.buf, pem.buflen)) != 0) {
			return (ret);
		}

		mbedtls_pem_free(&pem);
		return (0);
	} else if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {
		mbedtls_pem_free(&pem);
		return (ret);
	} else
#endif							/* MBEDTLS_PEM_PARSE_C */
		return (mbedtls_x509_csr_parse_der(csr, buf, buflen));
}

#if defined(MBEDTLS_FS_IO)
/*
 * Load a CSR into the structure
 */
int mbedtls_x509_csr_parse_file(mbedtls_x509_csr *csr, const char *path)
{
	int ret;
	size_t n;
	unsigned char *buf;

	if ((ret = mbedtls_pk_load_file(path, &buf, &n)) != 0) {
		return (ret);
	}

	ret = mbedtls_x509_csr_parse(csr, buf, n);

	mbedtls_zeroize(buf, n);
	mbedtls_free(buf);

	return (ret);
}
#endif							/* MBEDTLS_FS_IO */

#define BEFORE_COLON    14
#define BC              "14"
/*
 * Return an informational string about the CSR.
 */
int mbedtls_x509_csr_info(char *buf, size_t size, const char *prefix, const mbedtls_x509_csr *csr)
{
	int ret;
	size_t n;
	char *p;
	char key_size_str[BEFORE_COLON];

	p = buf;
	n = size;

	ret = mbedtls_snprintf(p, n, "%sCSR version   : %d", prefix, csr->version);
	MBEDTLS_X509_SAFE_SNPRINTF;

	ret = mbedtls_snprintf(p, n, "\n%ssubject name  : ", prefix);
	MBEDTLS_X509_SAFE_SNPRINTF;
	ret = mbedtls_x509_dn_gets(p, n, &csr->subject);
	MBEDTLS_X509_SAFE_SNPRINTF;

	ret = mbedtls_snprintf(p, n, "\n%ssigned using  : ", prefix);
	MBEDTLS_X509_SAFE_SNPRINTF;

	ret = mbedtls_x509_sig_alg_gets(p, n, &csr->sig_oid, csr->sig_pk, csr->sig_md, csr->sig_opts);
	MBEDTLS_X509_SAFE_SNPRINTF;

	if ((ret = mbedtls_x509_key_size_helper(key_size_str, BEFORE_COLON, mbedtls_pk_get_name(&csr->pk))) != 0) {
		return (ret);
	}

	ret = mbedtls_snprintf(p, n, "\n%s%-" BC "s: %d bits\n", prefix, key_size_str, (int)mbedtls_pk_get_bitlen(&csr->pk));
	MBEDTLS_X509_SAFE_SNPRINTF;

	return ((int)(size - n));
}

/*
 * Initialize a CSR
 */
void mbedtls_x509_csr_init(mbedtls_x509_csr *csr)
{
	memset(csr, 0, sizeof(mbedtls_x509_csr));
}

/*
 * Unallocate all CSR data
 */
void mbedtls_x509_csr_free(mbedtls_x509_csr *csr)
{
	mbedtls_x509_name *name_cur;
	mbedtls_x509_name *name_prv;

	if (csr == NULL) {
		return;
	}

	mbedtls_pk_free(&csr->pk);

#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
	mbedtls_free(csr->sig_opts);
#endif

	name_cur = csr->subject.next;
	while (name_cur != NULL) {
		name_prv = name_cur;
		name_cur = name_cur->next;
		mbedtls_zeroize(name_prv, sizeof(mbedtls_x509_name));
		mbedtls_free(name_prv);
	}

	if (csr->raw.p != NULL) {
		mbedtls_zeroize(csr->raw.p, csr->raw.len);
		mbedtls_free(csr->raw.p);
	}

	mbedtls_zeroize(csr, sizeof(mbedtls_x509_csr));
}

#endif							/* MBEDTLS_X509_CSR_PARSE_C */
